Hedge trimming device



J1me 1935- R. c. JOHNSEN HEDGE TRIMMING DEVICE Filed May 9, 1933 h rkINVENTOR Richard Cic/ohnsen ATTORNEY Patented June 25, 1935 UNITED,STATES PATENT OFFICE I e I 2,005,862 p HEDGE TRIMMI'NG' DEVICE 1 RichardCJJohnsen, Hillside, N. J. 7

Application May 9, 1933, Serial No. 670,078

8 Claims.

. This invention relates to hedge trimmers and particularly toelectrically operated machines of this character. I

An object of the inventionis to provide an improved device which islightin weight, easily manipulated and can be manufactured at low cost.

A further object is'to provide a device in which the drive is positiveand properly balanced.

Other objects and advantages of the invention will appear from thefollowing specification, reference being had to the accompanyingdrawing, in which like numerals denote like parts throughout.

Figure 1 is a view partly in section showing the front elevation of adevice embodying the invention;

Figure 2 is a side elevation of the device in Figure 1, having a portionof the casing cut away; I

Figure 3 is a view showing details of the drive mechanism of the devicein Figure 1;

Figure 4 is a view on line A-A of Figure 3;

Figure 5 is a view on line B--B of Figure 2;

Figure 6 is an enlarged view of the cutter blade tensioning means.

In the embodiment illustrated, there is a main plate I0 and a coverplate H which are suitably shaped to form a support and casing for theoperating mechanism. Main plate In and cover plate II have integralextended portions l2 and 13, respectively, having toothed formations I4in one edge thereof. Extending portions I2 and I3 are so shaped thatwhen brought together and secured by bolts or rivets 15 they form achannel in which cutter or knife frame I6 is operably mounted and a slot36 in which the cutter blade H is placed.

A power unit or motor I8 is mounted on main plate I0 and is providedwith a shaft i9 extending into housing 20. A worm gear 2M is fixedlymounted on shaft 19 and is in mesh with gear 2|, which in turn isfixedly mounted on shaft 22, rotatably disposed in housing 20.

On the opposite end of the shaft 22 is fixedly mounted eccentrically,two discs 23 and 230. which are in operable connection-with connectingrods 24 and 25. Connecting rod 25 is pivoted by screw 26 to the rear endof cutter frame I6 and connecting rod 24 is pivoted to lever 21, at 28.Lever 21 is loosely journaled to link 29 by pin 30, link 28 beingjournaled to main plate Ill by screw 3|. 7

The lever 21 has made integral therewith a gear segment 3| which is inmesh with the teeth thereof being of suitable form asshown alt-'33,

though any other suitable form may be'used.

Cutting knife I I being made of thin material has bothof its ends bentin the form of'ahook as shown at 34 and 35. v

A slot '31 is provided in the rear end "of {frame l6 which slot isengaged by hook 34 of knife' l 'li At the opposite end of the frame isprovided a tensioning means for knife l6 oonsistingof piece 38 having aslot 39 engaging hookand an extended portion 40, which passes looselythrough theupturned end of frame I6. Extended portion 40 has a slot 4iin its outerend .to receive cam '42 which is held in position and 'ro-'tateson pin 43.

The handle 44 is provided with a passageway through which passeselectrical conductors 45 for conveying current to motor [8. A switch 46is provided in handle 40 whereby lthe'current may be turned on and offas desired. A handle '41 is fixedly mounted on casing l0 for the properhandling of the device.

From the foregoing description of the details of the device itsoperation is easily understood.

In operation conductors 45 are connected to some suitable source ofelectrical energy, the operator grasps handles 44 and", depressesswitch'46 energizing motor I8, and causes it to rotate and in turnrotate worm 20a, gear 2 I, shaft 22 and eccentric disc 23, which throughconnecting rod 24 is operably connected to knifeframe I6, causing it toreciprocate.

To balance the moving parts of the mechanism, eccentric 23a is inoperable connection through connecting rod 24', lever 21, gear segment3| and rack 32 with knife frame It, thus tending to maintain a balancedrelation of the various moving parts. It is well understood that thedevice would be operable without the use of a second connecting rod andits associated parts, but by using these parts a smooth running and wellbalanced mechanism is obtained.

To compensate for the variable speeds of travel of connecting rods 24and 25 during their cycle of operation, lever 21 is mounted on a movablefulcrum provided by link 29, which is free to: swing within the limitsfixed by pins 41a and 48. Knife frame It carrying with it knife I! nowbeing reciprocated rapidly in relation to the stationary toothed membersbetween which it is placed, the hedge vegetation which may be in thespace beits reverse position, as shown by dotted lines.

This releases the tension on the knife and it can be easily removed. Toreplace the knife, the reverse procedure is employed.

It may be desired to operate the device by other power means, such as agas engine in which case the motor may be dispensed with and themechanism driven by a flexible shaft connected directly to the engine.

While a preferred form of the invention has been illustrated anddescribed, many changes can be made in the construction and. arrangementof 1 parts without departing from the scope of the invention as definedin the appended claims.

What is claimed is:

1. A hedge trimming device comprising a casing, saidcasing havingintegral extended portions forming a channel and tooth formations, saidtooth formations being spaced apart, a knife frame within said channelsupporting a flexible knife between said tooth formations, and meansincluding, a motor and a pair of lever rods connected thereto, one ofsaid rods being ,pivotally connected to said knife, the other of saidrods being linked to said casing.

2. A hedge trimming device comprising a casing, said casing havingextended portions forming a channel and tooth formations, said toothformations having serrated edges, aknife adjacent said tooth formations,and means including a motor and a pair of lever rods connected thereto,one of said rods being pivotally connected to said knife, the other ofsaid rods being linked to said casing.

3. In a hedge trimming device, a casing having extended portions forminga channel, a knife framemounted in said channel, an eccentricallymounted rotatable disc within said casing, a connectingrod in operablerelation with said disc and said knife frame, a second eccentricallymounted rotatable disc, and a second connecting rod in operable relationwith said second disc and through a lever and geari segments with saidknife frame, said lever being mounted on a movable fulcrum secured tosaid casing.

4. A hedge trimming device having a casing, a knife'frame supported bysaid casing, a'flexible knife mounted on said frame, means on said framefor holding said knife under fixed tension and means including a motorand a pair of lever rods connected thereto, one of said rods beingpivotally connected to said knife, the other of said rods being linkedto said casing.

5. A hedge trimming device, comprising an upper and a lower plateforming a casing, said plates having integral elongated portions forminga channel, said channel adapted to support a knife frame, a knife framein said channel, a flexible knife supported under tension on said frame,and means mounted on said casing and means including a motor and a pairof lever rods connected thereto, one of said rods being pivotallyconnected to said knife, the other of said rods being linked to saidcasing.

6. In a hedge trimming device a casing, having extended portions forminga channel, a knife frame mounted in said channel, an eccentricallymountedrotatable disc'within said casing, a connectingrod in operablerelation with said disc and knife frame, a second eocentrically mountedrotatable disc, and a'second connecting rod in operable relation tosaidsecond disc and through a lever and gear segments with said knife frame,said lever being mounted upon a fulcrum secured tosaid casing, saideccentrics being mounted to operate apart to actuate said connectingrods whereby said knife'is caused to reciprocate by the alternate actionof said rods.

7. A hedge-trimming device comprising a casing, a knife adapted toreciprocate therein, and motor means for reciprocating said knifecarried by said casing including a pair of levers one of said leversbeing connected to said motor means and pivoted on said knife, the otherof said levers being connected to said motor means and to a link movablysupported on said casing, whereby said knife may be reciprocated whilesaid levers are in substantially balanced relation.

8. In a hedge trimming device, a casing having portions forming anextended channeled arm, a

RICHARD C. JOHNSEN.

